Ignition Characteristics and Knock Limit in a Dual Fueled Diesel Engine (Case of Methanol and Gas Oil)

Abstract

Methanol was injected into each intake port of a 4 cylindered diesel engine and it was ignited by injecting a small amount of gas oil. The effects of the equivalence ration of methanol, the injection amount and the injection timing of gas oil, the intake temperature and the EGR rate on igtnition, the burninig rate of methanol and the knock limit were investigated experimentally. Ignition delay and the burning rate of methanol was compared with those of natural gas. It is found that the ignition delay of methanol is determined by the mean gas temperature at the ignition timing as is the same in the case of natural gas, and the onset of knocking is dominated by the mean gas temperature which is lower than the case of natural gas.